Printed Flexible Organic Transistors with Tunable Aspect Ratios

A fabrication technique that allows aspect ratio modulation in a large array of organic thin film transistors (OTFTs) is demonstrated. In this design, discrete interdigitated source and drain electrodes can be individually selected to create a range of aspect ratios (W/L). It is shown that by increasing the aspect ratio, the drain current is increased respectively. Arrays of OTFTs are fabricated with a combination of inkjet printing and surface energy patterned blade coating. OTFTs with optimized aspect ratios are interconnected to form electronic circuits with the desired performance. A fabricated enhancement‐load inverter with selected aspect ratios of 2000 µm/50 µm for the drive OTFT and 250 µm/50 µm for the load transistor show good switching performance with a dc gain of approximately 6 at supply voltage of −20 V.